There are only a handful of companies that have AAA ratings, so Apple's AA rating will make it popular with insurance companies and other institutions that need to hold high-quality assets, said Lurie.

"Everyone wants a bite of the Apple," she said, adding that the order book for Apple's offering is rumored to have already reached $40 billion.

Apple said earlier this month that it would tap the bond market as part of a plan to increase its share buyback program to $60 billion and boost its third-quarter dividend.

The move is unusual for Apple, which has not sold debt to the public since 1996.

Ben Rooney is a staff writer for CNNMoney. He covers the European debt crisis and other international finance stories, in addition to writing about stocks, bonds, investing and other Wall Street-related news. Follow Ben on Twitter: @ben_rooney